On existing aircraft, the engines such as double-flow and double-body turbojet engines are suspended below the wings by complex attachment devices, also called “EMS” (Engine Mounting Structure), or even attachment strut. The attachment struts usually employed have a rigid structure, called primary structure. This primary structure generally forms a box section, that is to say that it is constructed by the assembly of bottom and top longerons connected together by a plurality of transverse stiffening ribs, situated inside the box section. The longerons are arranged as bottom and top faces, while lateral panels close the box section as lateral faces.
As is known, the primary structure of these attachment devices is designed to allow the transmission to the wings of the static and dynamic loads generated by the engines, such as the weight, the thrust, or even the different dynamic loads.
In the solutions known from the prior art, the transmission of the loads between the engine and the primary structure is conventionally ensured by attachments consisting of a front engine mount, a rear engine mount and a thrust load take-up device. Together, these elements form an isostatic system of mounts.
Usually, the front engine mount is fixed to the outer shell of an intermediate casing or to the fan casing, as is disclosed in the document FR 3 014 841. Alternatively, this front engine mount can be added to the hub of the intermediate casing, linked by radial arms to the abovementioned outer shell. For its part, the rear engine mount links the primary structure to the exhaust casing of the engine, situated at the rear end of this engine.
With this type of configuration, loads of high intensity have to be taken up by the rear engine mount, notably the loads linked to the torque. To ensure the take-up of these significant loads, the rear engine mount usually has a significant bulk, particularly in the transverse direction. This strong bulk can for example be reflected by the presence of local protrusions at the two lateral ends of the rear engine mount. This causes, in the secondary jet, aerodynamic disturbances which are detrimental to the overall efficiency of the engine. Furthermore, there devolves therefrom an overdimensioning of the surrounding aerodynamic fairings, such as for the rear aerodynamic fairing (or APF, “Aft Pylon Fairing”), the width of which has to be adapted accordingly. These overdimensionings of the surrounding fairings also cause drag.
Moreover, the take-up of the loads at two points off-center from the longitudinal axis of the engine, respectively by the front engine mount and the rear engine mount, provokes a flexural deformation of the engine. This deformation leads to the wear of the blades of the high and low pressure turbines, and/or to the provision of significant gaps at blade end to limit their wear. In all cases, there devolves therefrom a loss of efficiency of the engine.